Drive clamp



March 3, 1959 E. l. UNGLESYBY DRIVE CLAMP Filed Sept. 8, 1955 IN VENTOR.

ELMER UNGLESBY ATTORNEYS United Sta -fit DRIVE CLAMP Elmer I. Unglesby,New Carlisle, Ohio Application September 8, 1955, Serial No. 533,050

g 3 Claims. (Cl. 255-1) This application relates to drive clamps fordriving well casings.

In drilling a well with a reciprocating type drill, it is customary tosuspend the drill from a walking beam and to rock the walking beam tosuccessively raise and drop the drill, thereby cutting a well bore inthe ground due to the crushing and cutting action of the drill. It iscustomary to line the well bore as the drilling takes place withsections of well casing, which are pieces of pipe having an internaldiameter sufficiently greater than the diameter of the drill in itsassociated drill string to permit reciprocation of the drill within thecasing. As the drilling progresses, sections of casing are driven intothe bore hole to line the bore hole as it is cut. The process might besimply described as a series of steps of alternately drilling anddriving casing.

To drive the easing into the bore hole a drive clamp is fastened to thedrill bit or to a link in the drill string above the drill bit. Thisdrive clamp extends laterally of the drill string for a distance greaterthan the diameter of the casing, and thus provides an abutment forstriking the top of the casing and driving it into the borev hole as thedrill string is reciprocated within the casing. Every time it is desiredto stop drilling operations and drive additional sections of casing itis necessary for a workman to climb the supporting tower of the walkingbeam and attach the drive clamp to the drill. This task requires theworkman to operate at a height which may be as great as thirty or fortyfeet, and at this height .to reach out and attach the clamp about adiametrically reduced portion of the drill string. Obviously this is arisky job and the attachment of the drive. clamp should be simplified inevery way possible to permit the workmen to attach the clamp quickly andeasily.

Accordingly, it is the primary object of this invention to provide adrive clamp of relatively simple and rugged construction which iscapable of rapid and easy attachment to a drilling rig.

Another object of the invention is to provide such a drive clamp whereina pair of jaws are hinged together for open and closing movement, andwherein each of the jaws has a recessed portion complementary to therecessed portion in the other jaw to provide a passage throughthe closedclamp for clamping around a reduced portion on the drill string.

An additional object of the invention is to provide such a drill clampwith a releasable locking means which may be readily engaged to lock thejaws in the closed position of the clamp thereby to retain the clamp onthe drill.

Another object of the invention is to provide in such a drive clampcomplementary notches in the sides of the jaws facing each other, whichnotches provide a passage of non-circular cross section through theclamp for clamping around a similarly non-circular portion of the drill.7

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawing and the appended claims.

f ice In the drawing- Fig. l is a, view partly in elevation and partlyin section showing an assembled drill string including the drive clampof the invention engaging a well casing pipe;

Fig. 2 is a perspective view of the drive clamp of .Fig. 1 in its closedposition;

Fig. 3 is a perspective view of the drive clampv in its open position;

Fig. 4 is a section on an enlarged scale taken on line 4-4 of Fig. l",and

Fig. 5 is an enlarged detailed section showing; the tapered locking pinin locking position.

Referring to the drawing, which illustrates a preferred embodiment ofthe present invention, and particularly to Fig. 1, the drill stringincludes a cable extended around a suitable pulley 12 carried on awalking beam (not shown). One end of cable 10 is clamped to a socket 13which is in turn coupled to a set of jars 14. The jars are connected inthe usual manner to a link 15 of the drill string, at the lower end ofwhich is carried a bit 18. The well bore cut by bit 18 is shown as linedwith a suitable casing pipe 20, sections of which are coupled togetherin the usual manner and driven into the bore. To drive the casing 20 adrive clamp indicated generally at is attached to the drill string, andreciprocation of the drill string causes clamp 25 to strike repeatedblows ,upon the top of casing 29 and drive it into the bore. Forexample, the clamp is reciprocated between the dotted line. and fullline positions in Fig. l to hammer on the top of casing 20. Once thecasing has been fully driven into the bore clamp 25 is removed from thedrill string and further drilling of the well bore is commenced andcontinued until it is necessary to drive additional casing, at whichtime the drill string is pulled up from the well and clamp 25 is againattached to drive the next length of casing.

, The clamp provided by the invention is shown in detail in Figs. 2 and3, and includes a pair of jaws 3i) and 32 articulated at one end to ahinged bar 33 by suitable hinged pins 34. Jaws and 3.2 are thus arrangedfor swinging movement about pins 34 between a closed position, shown inFig. 2, wherein the jaws are closely spaced and substantially parallelto each other, and an .open .position shown in Pig. 3, wherein the jawsdiverge with respect to each other from hinge bar 33. The adjacentcorners of jaws 3t) and 32 at the hinged ends thereof are relieved, asindicated at 35, to provide for free. swinging movement of the jaws.Thus, in the closed position of the jaws the inner face 36 of jaw 30,and the inner face 38 of jaw 32 are adjacent to each other and may beeither abutting or relatively closely spaced apart.

I Each of the inner faces 36 and 38 is provided with a transverse,preferably fiat-sided, recess shown as'notches 40 and 42, respectively,extending across the inner faces of the jaws. It is to be understoodthat the particular notched configuration of these recesses shown in thedrawing is merely exemplary and they may be of any desirable crosssection. Preferably, recesses 40 and 42 are complementary to each otherand are of non-circular configuration in combined cross section.

The other or free ends of jaws .30 and 32 are provided with :slots 44and 45 extending longitudinally into the free ends of the jaws. Alocking bar 58 is hinged within slot 44 on jaw 30 by a hinged pin 51,and is free to move from the position shown in Fig. 3, wherein barextends substantially at right angles toface 36 of jaw 30, to a position.extending outwardly from the end of the jaw. The direction of swingingmovement of bar 50 is indicated by arrow 52 in .Fig. 3. The free orouter end of bar 50 is receivable within slot 45 on fi w and a o 5. 1s Pi d t r u her 5 to e 'tend through the locking bar on the outer face ofjaw 32 .to the end of bar 50 by swings the clamp shut about portion 70.

clamp comprising in the closed position of the clamp as shown in Fig. 2,transverse slots 56 are formed in the outer face of jaw 32, across oneside of notch 45, and arranged to be aligned with slot 55.

A tapered locking pin 60, having a flat face 61 and a tapered roundedface 62, is provided for retaining locking bar 50 in slot 45. The pin 60is preferably attached a chain 64 to prevent misplacing of the pin, andmore important, to prevent difficulties should a workman lose his graspon the pin while attaching the clamp to the drill string at a relativelygreat height. The degree of taper on surface 62 is within the range ofself-locking tapers for the material used, and thus when the pin 60 isinserted to lock the clamp, manual force on the pin will be sufiicientto secure it within the slot 55 against accidental loosening. The lengthof pin 60 is preferably slightly greater than the height or thickness ofjaw 32, as will be apparent from inspection of Fig. 5. This provides fora protrusion of the smaller end of the tapered pin below slots 56, andthus the pin may. be knocked loose by tapping its smaller end with ahammer or the like should it become wedged tightly within the slotsduring use of the clamp.

Jaws 30 and 32 are provided with handles 65 and 66 for ease ofmanipulating the clamp. These handles are unnecessary to the operationsof the clamp, but they do greatly facilitate the overall ease ofattachment and removal of the clamp with respect to' the drill string.To operate the clamp the workman climbs the tower until he reaches theheight of the non-circular portion 70 (Fig. 4) of the link 15. With theclamp in its open position, as in Fig. 3, he then grasps handles 65 and66 and Thus, the recesses 40 and 42 cooperate to provide a passagethrough the closed clamp which conforms generally to the cross sectionof link portion 70. The upper and lower edges of the jaws rest againstthe shoulders 71 and 72 on opposite sides of the reduced portion 70, andthe clamp is thus fixed upon the drill string so long as it ismaintained in its closed position. To lock the clamp it is onlynecessary to swing bar 50 into slot 45 and firmly insert the pin 60through slots 55 and 56.

The attachment and removal of the clamp with respect to the drill stringis therefore a simple matter, requiring but a few moments, and with notightening of screws, bolts or the like being necessary. Thus theworkman does not have to carry tools with him and manipulate these toolswhile retaining his hold on the tower. At the most, should pin 60 becomefirmly wedged in its locking position, it would be necessary only to rapthe bottom of the pin to loosen it and no turning or tighteningofthreaded members is operation of the clamp. It is to be understood thatsuch loosening of the pin as described above would be an unusualcircumstance, since in the average case the pin would not be so firmlywedged in place as to require striking force to remove it..

required at any time in -Thus, it is seen that the present inventionprovides a drive clamp which is of rugged yet simple construction, andwhich is capable of easy and rapid operation for attachment to andremoval from a drill string. No tools areneeded for operation of theclamp, and no prolonged tightening operations are required of theworkman While he is, manipulating the clamp at a relatively greatheight.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

l. A drive clamp for attachment to a reciprocating drill string havingspaced shoulder. portions thereon, said a pair of jaws hinged togetherat one 4 end thereof for swinging movement between an open positionwherein said jaws are diverging and a closed position wherein said jawsare in substantially parallel side by side relation, the lower surfacesof said jaws being substantially flat and coplanar defining a strikingsurface for engaging and driving well casing releasable means forlocking said jaws in said closed position, said clamp having atransverse passage therein of lesser cross section than said shouldersand of sutficient cross section to encompass the drill string betweensaid shoulders, said passage being provided by complementary recesses insaid jaws to provide for attachment and removal of said clamp on thedrill string by swinging said jaws to said open position, and thethickness of said clamp about said passage being slightly less than thedistance between said shoulders to retain said clamp in closed positionagainst movement relative to the drill string for striking driving wellcasing through which the drill string itself is freely movable.

2. For use in a well drilling rig having a diametrically reduced portionof relatively short length axially of the drill and adapted forreciprocating drilling action within a tubular well casing, a clamp ofgreater cross section than the passage of the well casing and adapted tobe removably secured around the diametrically reduced portion of thereciprocating drill for movement therewith to drive the well casing intothe well bore as drilling progresses, comprising a pair of jaws hingedtogether at one end for swinging movement between closed and openpositions of the clamp, the lower surfaces of said jaws beingsubstantially fiat and coplanar defining a striking surface for engagingand driving well casing each of said jaws having a fiat-sided recessformed transversely thereof, said recesses being complementary to eachother to provide a passage through the closed clamp slightly larger thansaid reduced portion on said drill and smaller than the remainder ofsaid drill, and releasable locking means for retaining said clamp inclosed position clamped around said reduced portion and providing foropening of said clamp to facilitate attachment thereof to the drill fordriving casing and removal of said clamp from the drill for furtherdrilling of the well.

3. For use in a well drilling rig having a diametrically reduced portionof relatively short length axially of the drill and adapted forreciprocating drilling action within a tubular well casing, a clamp ofgreater cross section than the passage of the well casing and adapted tobe removably secured around the diametrically reduced portion of thereciprocating well drill for movement therewith to drive the well easinginto the well bore as drilling progresses, comprising a pair of jawsarticulated to a hinge barfor movement toward and away from each otherto close and open the clamp, the lower surfaces of said jaws beingsubstantially flat and coplanar defining a striking surface for engagingand driving well casing each of said jaws having a relieved portionformed in the side thereof facing the other said jaw and extendingtransversely of the jaw, said relieved portions being complementary toeach other to provide a passage through said clamp in the closedposition of said clamp, said passage being of such cross section as tofit around the reduced portion of the drill and of lesser cross sectionthan the portions of the drill immediately adjacent the reduced portionfor retaining said clamp in a longitudinally fixed position on thedrill, a locking bar hinged to the free end of one of said jaws, theother said jaw having a slot in the free end thereof for receiving saidlocking bar, means defining a slot in the free end of said locking barextending beyond said slot in said other jaw in the closed position ofsaid clamp, a pin receivable in said slot in said locking bar, and meansfor retaining said pin relative to said free end of said other jaw andwithin said slot in said locking bar. I

(References on followim page) blows upon I References Cited in the fileof this patent UNITED STATES PATENTS Saunders Mar. 17, 1891 Richey Sept.27, 1898 5 Carpenter Dec. 19, 1899 6 Berg Apr. 15, 1919 Lonergan Feb.14, 1922 Pringle Jan. 4, 1927 Monroe Aug. 25, 1936 Ekin Jan. 21, 1941Stanley Oct. 28, 1941

